1. Field of the Invention
This invention relates broadly to surgical instruments. More particularly, this invention relates to probe-like cutting instruments for use in surgical procedures.
2. State of the Art
The development of minimally invasive surgical procedures, such as endoscopic and laparoscopic procedures, has created a great demand for devices well-adapted for use during such procedures. More particularly, when performing port access surgery, such as when endoscopically performing an arteriotomy, it is sometimes necessary to make very accurate incisions. Because of the limitations imposed by the entry site with respect to the location and orientation of the surgical site, it is desirable to be able to control the blade penetration depth as well as the approach angle of the blade toward the surgical site. The latter allows the surgeon to make an incision in the plane that is most desirable. Generally, this angle would be perpendicular to the surface being incised.
It is therefore an object of the invention to provide an endoscopic surgical knife in which the depth of the blade exposure can be finely controlled while the device is in use.
It is another object of the invention to provide an endoscopic surgical knife in which the angle of the blade can be controlled while the device is in use.
It is a further object of the invention to provide an endoscopic surgical knife which remains stable at a desired angle.
It is an additional object of the invention to provide an endoscopic surgical knife in which the blade is completely retractable so that it does not become damaged or cause damage upon introduction through or withdrawal from a port.
It is also an object of the invention to provide an endoscopic surgical knife having a relatively small shaft.
It is still another object of the invention to provide an endoscopic surgical knife which maximizes the blade size relative to the shaft.
In accord with these objects, which will be discussed in detail below, a surgical knife device is provided which includes a tubular shaft, a blade guide at the distal end of the shaft, a blade depth control member extending through the shaft, and a blade coupled to the distal end of the blade depth control member. A proximal handle moves the blade depth control wire relative to the shaft such that the blade moves relative to the blade guide. According to a preferred aspect of the invention, the blade height is substantially the same as the outer diameter of the distal end of the shaft and the blade guide. As such, the blade has a relatively large cutting surface. The blade is moved between a retracted position in which the blade is positioned substantially completely within the blade guide and an extended position in which at least a portion of the blade extends distally from the blade guide.
According to another preferred aspect of the invention, movement of the blade between retracted and extended positions is effected with a knob rotatably coupled to the handle. The knob includes an axial threaded bore, and the proximal end of the blade depth control member is provided with a threaded adapter which at least partially resides in the bore of the knob. When the knob is rotated, the adapter is longitudinally moved within the bore and the blade depth control member coupled to the blade is likewise longitudinally moved to effect movement of the blade. Using the knob, fine and controllable longitudinal movement of the blade is enabled.
According to a further preferred aspect of the invention, steering members extend from the handle through the shaft on either side of the blade depth control member and are coupled to adjacent a flexible distal portion of the shaft. The handle is provided with a means, e.g., a steering knob, for moving one steering member relative to the other to cause the shaft to bend about a flexible distal portion such that the device is articulable.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.